Rope rescue is essentially an access and transportation issue of moving a subject or patient from a place of predicament to a place of care. Ropes are used to raise, lower, and even horizontally move a patient and/or rescue attendant. This is accomplished with the use of variable-friction descent control devices, mechanical advantage systems such as pulley systems, rope grabs, brake or hitch devices, and back-up devices such as force limiting rope brakes. However, no prior art device of which Applicant is aware can perform the combined functions of variable friction descent control, efficient pulley with a built-in ratchet, and a belay device capable of handling rescue-sized loads, in one simple device.
Conventionally, to convert from a lower to a raise usually requires a series of steps to accomplish. First, in order to remove the descent control device, the rope is held with some form of rope grab, such as a brake, gripping hitch or mechanical rope grab. Once the descent control device is removed, rescuers may then build a pulley system, either made out of the mainline itself, or a separate pre-rigged pulley system is attached to the mainline. The pulley system usually remains on top of the cliff, building or structure, above the patient, where it is within a practical working distance of the rescuers. In order to completely raise the load to the top, multiple ‘resets’ of the pulley system are required. To reset the pulley system, the mainline has some form of a rope grab, often called a “ratchet” or “progress capture device”, usually positioned at the first anchor pulley where the descent control device was mounted.
In addition to the mainline, a common practice in rope rescue is to also incorporate a separately anchored, un-tensioned back-up rope, often called a “belay” or “safety” line, which is intended to catch the falling load should anything inadvertently happen to any component within the mainline system. Again, this line is typically managed with specialized force-limiting rope grabs. This device must be capable of easily taking in or letting out rope as the load is being raised or lowered, and must be able to withstand a shock force and quickly arrest the falling load should anything within the mainline system fail. Thus it may be seen that, conventionally, multiple tasks and equipment are needed to change over from a lower to a raise, or from a raise to a lower, and to manage a belay/safety line.
A number of devices can accomplish both lowering and raising, such as mechanical winches. Related to winches are capstan-style drums that allow the drum to rotate one direction (while raising), but not the other, so that lowering can be accomplished by placing multiple wraps around the capstan for friction. Some products also incorporate a cam cleat to serve as a ‘ratchet’ so that a pulley system may be rigged utilizing the same device. But rope rescue winches and related capstan-style drums are large, heavy and generally quite expensive, and are not used to also manage the belay/safety line.
Other conventional devices may be used to lower or rappel with, and may hold the mainline like a ratchet, but in Applicant's experience these devices are not rated for rescue-sized loads. These devices cannot efficiently be used as a pulley in a haul system since their internal ‘pulley’ does not ‘freewheel’ while the load is being raised. They can be used as for belay, but only for one-person loads, and are very specific to a narrow range of rope diameters.